This invention relates to an apparatus for closing a fireproof door, normally locked in its open position, in case of emergency such as fire either by remote-controlled energization of a solenoid or with a manual closing force.
In a prior art closing apparatus, a slider normally latched by a latch mechanism is released by remote-controlled energization of a solenoid in case of fire and the door is automatically closed by, for instance, a door closer.
It is desired, however, to manually release a slider from a latch mechanism so as to close the door manually, thereby assuring a reliable operation even when a solenoid malfunctions.
Further, in the prior art closing apparatus, latching force of the latch mechanism is normally set to a level higher than necessary to prevent a slider from becoming unintentionally released. It is desired, also, to make it possible to adjust the latching force of the latch mechanism since manual closing becomes difficult when latching force of the latch mechanism is excessive.